In this chapter, you'll get a quick look at what Visual Basic.NET is, and what's new in this version. You'll also get an idea of the work involved in upgrading older applications from VB6 to VB.NET, and a brief introduction to the .NET Framework.

This pre-publication chapter is from Sams Teach Yourself More VB.NET in 21 Days, by Lowell Mauer (0672322714). Content is based on a pre-Beta 2 build of Microsoft's .NET technology.

Welcome to the next generation of Visual Basic. In every new release of
Visual Basic, Microsoft has added many new features, enhanced some others, and
removed or replaced some older capabilities. With the release of Visual
Basic.NET, Microsoft has done it again. In fact, Visual Basic.NET brings
together new technologies that will make your applications more efficient,
easier to deploy, and Web-enabled.

Today, you get a quick look at what Visual Basic.NET is, and what's new
in this version. Along the way, you will get an idea of the work involved in
upgrading older applications from VB6 to VB.NET. One of the biggest changes that
Microsoft has made is the inception of the .NET Framework. We will introduce
this new environment today and cover it in a little more detail on Day 4,
"Understanding the .NET Framework." You also will look at what it
takes to transition from Visual Basic 6 to the new .NET environment.

You will also see what drives the type of application you're creating.
This involves choosing an application that makes sense and creating a life cycle
or project plan for the application that takes it from an idea to the final
product.

Also, you'll start a new demo project in Visual Basic. Although you
probably know how to do this already, it's a good idea to review it. You do
this not just for the steps needed, but to discuss the options available to you
with the project properties, focusing on what they can do for you during the
development and testing process. Naming conventions will also be covered;
however, you won't be shown lists of what they should be. Instead,
you'll learn why you need them and how they should be used.

Finally, at the end of today's lesson, some of the more advanced
controls and features included in Visual Basic will be covered. You'll see
what they are, how to use them individually and together, and—more
importantly—why you should use them.

A Brief Look at What's New in Visual Basic.NET

Visual Basic.NET is the next version of Visual Basic. Rather than simply add
some new features to Visual Basic 6.0, Microsoft reengineered the product to
make it easier than ever before to write distributed applications such as Web
and enterprise systems. Visual Basic.NET has two new packages for creating forms
(Windows Forms and Web Forms); a new version of ADO for accessing disconnected
data sources; and has streamlined the language, removing older, unused keywords,
among other changes.

These new features will allow you to create both client/server applications
and Internet-based applications. With Web Forms and ADO.NET, you can now rapidly
develop scalable Web sites. With the addition of inheritance, the language is
now an object-oriented programming environment. Windows Forms natively supports
accessibility and visual inheritance. Finally, deploying your applications is
now as simple as copying your executables and components from directory to
directory.

Also, Visual Basic.NET is now fully integrated with the other Microsoft
Visual Studio.NET languages. Not only can you develop application components in
different programming languages, but also your classes can now inherit from
classes written in other languages using cross-language inheritance. With the
unified debugger, you can now debug multiple language applications, whether they
are running locally or on remote computers. Finally, whatever language you use,
the Microsoft .NET Framework provides a rich set of APIs for use in Windows and
the Internet.

Changes to the Visual Basic Language

Whereas earlier versions of Visual Basic had been directed toward standard
client applications, Visual Basic.NET is intended for creating Web service
applications as well as the standard Windows client applications. This is done
by generating managed code for the .NET framework and Common Runtime (discussed
later in this section). This, of course, required significant changes to the
Visual Basic language.

Although Visual Basic has retained many of its original features, modified
and enhanced others, and added new features, it's inevitable that this led
to some inconsistency and redundancy within the language. With the major changes
required for the .NET Framework and runtime, Microsoft decided that it was a
good opportunity to clean up many of the outdated aspects of the Visual Basic
language.

The changes that were made are intended to do the following:

Simplify the language and make it more consistent

Add new features that have been requested

Make the code easier to read and maintain

Enhance the error processing

Make applications easier to debug

The New Windows Forms

Windows Forms is part of the new.NET Framework and leverages many new
technologies including a common application framework, managed execution
environment, integrated security, and object-oriented design principles. Windows
Forms also offers full support for quickly and easily connecting to XML Web
services and building rich, data-aware applications based on the ADO.NET data
model. With the new shared development environment in Visual Studio, developers
can create Windows Forms applications with any languages supporting the .NET
platform.

Creating a Windows Forms application is done much the same way as it was done
in previous releases of Visual Basic. Controls are placed on the form and then
positioned as required. To edit the source code, simply double-click a control
to open the source editor.

Visual Inheritance

Visual inheritance is one key new feature available in Windows Forms that
will enhance developer productivity and facilitate code reuse. For example, you
could define a standard main form that contains items such as a standard main
menu and perhaps a common toolbar. This form can be used in other applications
through inheritance and extended to meet the requirements of specific
applications while promoting a common user interface and reducing the need to
re-create the same forms. The creator of this base form or template can specify
which elements can be extended and which must be used as-is, ensuring that the
form is reused appropriately.

Precision Form Design

With the new Windows Forms, you now have an unprecedented level of control
and productivity when designing the look and feel of your applications. Features
such as the Menu Designer, Anchoring, Docking, and many other new controls
enable a higher level of power and precision for developers building rich
Windows-based user interfaces.

Windows Forms provides you with a rich set of technologies for building
Windows-based applications. Not only are there new controls and features for
fine-tuning the user interface, but Windows Forms also provides flexible
deployment and integrated security.

The New Web Forms

Web Forms was created to address the differences between the techniques in
use to build a Windows application and those used to create a Web application.
With Visual Basic.NET you can now rapidly develop applications that will run on
the Internet using the exact same techniques that you have already learned in
Visual Basic.

To create a Web application, simply add a Web Form to your project, drag the
controls you need onto the page, and then double-click each control to add the
code required. Web Forms provides the following advantages:

Separates the HTML layout from the code behind the page. This separation
makes it easier to update either piece independently of the other, simplifying
code navigation and enabling code to be versioned more easily

Greatly enhances runtime performance because the code behind the HTML
page is compiled into an executable, not script

Generates HTML pages in HTML 3.2, which means the page can be viewed on
any platform, with any browser. Alternatively, you can target the special
capabilities of a specific browser or wireless device

Previous versions of Visual Studio tools have attempted to simplify Web
development. For example, Visual Basic provided support for DHTML clients and
WebClasses while Visual InterDev assisted in the development of Active Server
Pages (ASP). Web Forms address these issues and are the fundamental way to build
Web applications with Visual Basic.NET. Web Forms represent an evolution of ASP
and WebClasses providing the best of both models.

Transitioning from Visual Basic 6

Microsoft considered two options when designing Visual Basic.NET: retrofit
the existing code base to run on top of the .NET Framework, or build from the
ground up, taking full advantage of the platform. To deliver the features most
requested by customers (for example, inheritance and threading) and ensure that
Visual Basic moves forward into the next generation of Web applications, the
decision was made to build Visual Basic.NET from the ground up on the new .NET
Framework.

Visual Basic.NET enables a fundamental shift from traditional Windows
development to building next-generation Web and Windows applications. For this
reason, your code will need to be upgraded to take advantage of Visual
Basic.NET. Thankfully, Microsoft has provided an Upgrade Wizard to help you
perform this task. When you open a Visual Basic 6 project in Visual Basic.NET,
the Upgrade Wizard will automatically start to step you through the upgrade
process and will create a new Visual Basic.NET project, leaving your existing
project untouched.

When your project is upgraded, the language is modified for any syntax
changes and your Visual Basic 6.0 Forms are converted to Windows Forms. In most
cases, you will have to make some changes to your code after it's upgraded.
This is required because certain objects and language features either have no
equivalent in Visual Basic.NET, or have an equivalent too different for an
automatic upgrade. After the upgrade, you may also want to modify your
application to take advantage of some newer features in Visual Basic.NET.

When you use the Upgrade Wizard, most required language and object changes
will be made for you. The Upgrade Wizard is started when you open a Visual Basic
6 application. It will ask you about the project type and set options for your
application (see Figure
1.1). At this moment, leave the defaults displayed.

The next step is to specify where you want the new .NET project to be saved.
Remember that your original project won't be modified. Once completed,
the new project will remain open in the Solutions Explorer. You can then display
the Upgrade report to see what issues you need to resolve as shown in
Figure
1.2.

Figure 1.2 Working
with the Upgrade report to resolve Visual Basic language issues.

Two very good documents are available from the Microsoft Visual Basic.NET Web
site: